CVE-2026-33173
MediumCVSS 5.3Summary
Active Storage in Rails applications prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 allows DirectUploadsController to accept arbitrary metadata from the client and persist it on the blob. Because internal flags like identified and analyzed are stored in the same metadata hash, a direct-upload client can set them to skip MIME detection and analysis, allowing upload of arbitrary content while claiming a safe content_type and bypassing validations.
Risk Assessment
An attacker can upload arbitrary content while masquerading as a safe content type and bypass validations based on automatic MIME detection. This may lead to storage and distribution of malicious files within the application.
Recommendation
Update Rails/Active Storage to version 8.1.2.1, 8.0.4.1, or 7.2.3.1 (or newer). Until patched, consider restricting or disabling direct uploads and verifying file types server-side.
Other vulnerabilities in Active Storage
See all- CVE-2026-33658Medium
Active Storage in Rails applications allows users to attach cloud and local files. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, the proxy controller does not limit the number of byte ranges in an HTTP Range header, so a request with thousands of small ranges causes disproportionate CPU usage and may lead to a DoS vulnerability.
- CVE-2026-33202Critical
In Active Storage (Ruby on Rails) prior to versions 8.1.2.1, 8.0.4.1 and 7.2.3.1, DiskService#delete_prefixed passes blob keys directly to Dir.glob without escaping glob metacharacters. If a blob key contains attacker-controlled input or glob metacharacters, unintended files may be deleted from the storage directory.
- CVE-2026-33195Critical
A path traversal vulnerability in Active Storage's `DiskService#path_for` allows arbitrary file access if blob keys contain `../` sequences. Attackers can read, write, or delete files outside the storage root.
- CVE-2025-24293High
A vulnerability in Active Storage allows bypassing default security restrictions for image transformation methods, potentially leading to command injection when user-supplied input is accepted as transformation methods or parameters. The issue affects applications using Active Storage with the image_processing gem and mini_magick as the image processor.
Original NVD description (English source)
Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS